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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"><html><head><meta http-equiv="Content-Type" content="text/html;charset=iso-8859-1"><title>Crypto++: rc6.cpp Source File</title><link href="doxygen.css" rel="stylesheet" type="text/css"></head><body><!-- Generated by Doxygen 1.3.2 --><div class="qindex"><a class="qindex" href="index.html">Main Page</a> | <a class="qindex" href="namespaces.html">Namespace List</a> | <a class="qindex" href="hierarchy.html">Class Hierarchy</a> | <a class="qindex" href="classes.html">Alphabetical List</a> | <a class="qindex" href="annotated.html">Compound List</a> | <a class="qindex" href="files.html">File List</a> | <a class="qindex" href="namespacemembers.html">Namespace Members</a> | <a class="qindex" href="functions.html">Compound Members</a> | <a class="qindex" href="globals.html">File Members</a></div><h1>rc6.cpp</h1><div class="fragment"><pre>00001 <span class="comment">// rc6.cpp - written and placed in the public domain by Sean Woods</span>00002 <span class="comment">// based on Wei Dai's RC5 code.</span>00003 00004 <span class="preprocessor">#include "pch.h"</span>00005 <span class="preprocessor">#include "<a class="code" href="rc6_8h.html">rc6.h</a>"</span>00006 <span class="preprocessor">#include "misc.h"</span>00007 00008 NAMESPACE_BEGIN(CryptoPP)00009 00010 <span class="keywordtype">void</span> RC6::Base::UncheckedSetKey(CipherDir direction, <span class="keyword">const</span> byte *k, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> keylen, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> rounds)00011 {00012 AssertValidKeyLength(keylen);00013 AssertValidRounds(rounds);00014 00015 r = rounds;00016 sTable.New(2*(r+2));00017 00018 <span class="keyword">static</span> <span class="keyword">const</span> RC6_WORD MAGIC_P = 0xb7e15163L; <span class="comment">// magic constant P for wordsize</span>00019 <span class="keyword">static</span> <span class="keyword">const</span> RC6_WORD MAGIC_Q = 0x9e3779b9L; <span class="comment">// magic constant Q for wordsize</span>00020 <span class="keyword">static</span> <span class="keyword">const</span> <span class="keywordtype">int</span> U=<span class="keyword">sizeof</span>(RC6_WORD);00021 00022 <span class="keyword">const</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> c = STDMAX((keylen+U-1)/U, 1U); <span class="comment">// RC6 paper says c=1 if keylen==0</span>00023 <a class="code" href="class_sec_block.html">SecBlock<RC6_WORD></a> l(c);00024 00025 GetUserKey(LITTLE_ENDIAN_ORDER, l.<a class="code" href="class_sec_block.html#_sec_block_with_hinta7">begin</a>(), c, k, keylen);00026 00027 sTable[0] = MAGIC_P;00028 <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> j=1; j<sTable.size();j++)00029 sTable[j] = sTable[j-1] + MAGIC_Q;00030 00031 RC6_WORD a=0, b=0;00032 <span class="keyword">const</span> <span class="keywordtype">unsigned</span> n = 3*STDMAX((<span class="keywordtype">unsigned</span> <span class="keywordtype">int</span>)sTable.size(), c);00033 00034 <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> h=0; h < n; h++)00035 {00036 a = sTable[h % sTable.size()] = rotlFixed((sTable[h % sTable.size()] + a + b), 3);00037 b = l[h % c] = rotlMod((l[h % c] + a + b), (a+b));00038 }00039 }00040 00041 <span class="keyword">typedef</span> BlockGetAndPut<RC6::RC6_WORD, LittleEndian> Block;00042 00043 <span class="keywordtype">void</span> RC6::Enc::ProcessAndXorBlock(<span class="keyword">const</span> byte *inBlock, <span class="keyword">const</span> byte *xorBlock, byte *outBlock)<span class="keyword"> const</span>00044 <span class="keyword"></span>{00045 <span class="keyword">const</span> RC6_WORD *sptr = sTable;00046 RC6_WORD a, b, c, d, t, u;00047 00048 Block::Get(inBlock)(a)(b)(c)(d);00049 b += sptr[0];00050 d += sptr[1];00051 sptr += 2;00052 00053 <span class="keywordflow">for</span>(<span class="keywordtype">unsigned</span> i=0; i<r; i++)00054 {00055 t = rotlFixed(b*(2*b+1), 5);00056 u = rotlFixed(d*(2*d+1), 5);00057 a = rotlMod(a^t,u) + sptr[0];00058 c = rotlMod(c^u,t) + sptr[1];00059 t = a; a = b; b = c; c = d; d = t;00060 sptr += 2;00061 }00062 00063 a += sptr[0];00064 c += sptr[1];00065 00066 Block::Put(xorBlock, outBlock)(a)(b)(c)(d);00067 }00068 00069 <span class="keywordtype">void</span> RC6::Dec::ProcessAndXorBlock(<span class="keyword">const</span> byte *inBlock, <span class="keyword">const</span> byte *xorBlock, byte *outBlock)<span class="keyword"> const</span>00070 <span class="keyword"></span>{00071 <span class="keyword">const</span> RC6_WORD *sptr = sTable.end();00072 RC6_WORD a, b, c, d, t, u;00073 00074 Block::Get(inBlock)(a)(b)(c)(d);00075 00076 sptr -= 2;00077 c -= sptr[1];00078 a -= sptr[0];00079 00080 <span class="keywordflow">for</span> (<span class="keywordtype">unsigned</span> i=0; i < r; i++)00081 {00082 sptr -= 2;00083 t = a; a = d; d = c; c = b; b = t;00084 u = rotlFixed(d*(2*d+1), 5);00085 t = rotlFixed(b*(2*b+1), 5);00086 c = rotrMod(c-sptr[1], t) ^ u;00087 a = rotrMod(a-sptr[0], u) ^ t;00088 }00089 00090 sptr -= 2;00091 d -= sTable[1];00092 b -= sTable[0];00093 00094 Block::Put(xorBlock, outBlock)(a)(b)(c)(d);00095 }00096 00097 NAMESPACE_END</pre></div><hr size="1"><address style="align: right;"><small>Generated on Tue Jul 8 23:34:23 2003 for Crypto++ by<a href="http://www.doxygen.org/index.html"><img src="doxygen.png" alt="doxygen" align="middle" border=0 > </a>1.3.2 </small></address></body></html>⌨️ 快捷键说明
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